unless (
  check_lib(     # fill in what you prompted the user for here
    #lib => [qw(expat)],
    header => ['expat.h'],
    debug => 1,
    incpath => $expat_incpath,
    # Ugly hack here
    ($expat_libpath?
    (libpath => "$expat_libpath -lexpat"):()),
  )) {